Electrode clamps



March 20, 1962 c, SLQCOMBE ETAL 3,026,444

ELECTRODE CLAMPS Filed Sept. 22,. 1959 2 Sheets-Sheet 1 M 96% Add/ INVE TORS c. M. SLOCOMBE ETAL 3,026,444

March 20, 1962 ELECTRODE CLAMPS 2 Sheets-Sheet 2 Filed Sept. 22, 1959 INVEN TORS YPRI'AN M. SLOCOMBE BENN 01(E RN Unite States This invention has reference to electrode clamps and is concerned, more particularly, with electrode clamps of electric arc furnaces.

The principle object of the present invention is to reduce the costs of manufacture of the clamps and to minimise their liability to fail, by reducing the number of cast copper, current conducting components which are are not only expensive to manufacture but are also difiicult to produce free of faults.

A further object of the invention is to provide an improved electrode clamp of which the component parts are readily accessible, thereby facilitating assembly and also, when desired, the dismantling of the clamp.

Still another object of the invention, when applied to a'clamp intended to be incorporated in an arc furnace, is to enable a heat shield to be assembled thereto in a simple and speedy manner which minimises buckling of the shield under the action of heat generated in and radiated from the furnace.

The above and other objects of the invention will be apparent from the following description when read in conjunction with the accompanying drawings which show, by way of example, one mode of carrying the invention into effect.

In the said drawings:

FIGURE 1 is an elevation and FIGURE 2 is a plan of a clamp primarily intended for holding an electrode of an electric arc furnace, and

FIGURE 3 is a section along the line III--III, of FIGURE 2.

The clamp shown in the drawing comprises a current conducting shoe 1 which is accommodated within a holder 2, and a strap 3 which is mounted on the holder and is slidable relatively to the said holder towards and away from the shoe. The shoe consists of a copper casting whereas the holder and strap are fabricated from a ferrous or any other convenient metal which, compared with copper, is inexpensive and is easy to fabricate free of faults.

The holder is of U-shape in transverse section and comprises a base 4 from the opposite edges of which two side cheeks 5 project in the same direction; the lower end of the said base is provided with a shelf or platform 6 which extends across the lower edges of the roots of the said cheeks and serves as a support for the shoe. Each cheek is formed on its external surface and between its upper and lower edges, with two laterally-projecting, parallel lugs 7 which reach from the cheek edge remote from the holder base, part way across the cheek.

The strap is of U-shape, is of a depth considerably less than the depth of the shoe, its closed and semi-circular end 8 is located beyond and bridges the opening between the side cheeks 5 and its arms 9 embrace the said cheeks, are disposed between and are slidable longitudinally of the lugs on the respective cheeks, their free ends projecting beyond the said lugs towards the holder base, and each of the said free end-s has a longitudinal slot 10 which opens to the upper and lower edges of the corresponding arm.

The strap is reciprocable relatively to the holder by an operating lever 11 of which the branches 12 of the lower forked end embrace the holder base and extend atent able from the base of the holder.

respectively through the slots 10, the lower free ends of the said branches being journalled about one and the same pivot pin 13 which extends through and is remov- By journalling the branches about the common removable pin, the initial assembly of the strap and lever upon the holder, and subsequent dismantling, if and when necessary or desirable, of the said strap and lever, is facilitated.

The clamp is carried upon one end of a horizontal rod 14 which projects above, and is adapted to be raised and lowered relatively to, the furnace into the working chamber of which an electrode 14, gripped between the shoe and strap of the clamp, depends, the base of the holder being bolted to a flange around a crosshead 15 fixed upon and electrically insulated from the said rod end.

The platform supported shoe has a recess 16 in its face which sea-ts upon the internal surface of the holder base and a lip 17 provided on the upper end of the shoe, projects over and beyond the upper edge of the said base where it is bolted and electrically connected to plates 18 on two bus tubes 19 mounted above and parallel to the clamp-carrying rod and crosshead, the said tubes serving, first, as current conductors to the shoe and, secondly, as ducts for a fluid coolant.

The face of the shoe remote from the holder base is concave in transverse section and is ribbed transversely I so that it is adapted to seat part way round, and to effect a firm hold on, the electrode.

A sinuous or like duct 20 cast into the shoe, is incorporated in a coolant circulating system by a pipe 21 connected into and between one end of the duct and the bore of one of the bus tubes, at second pipe 22 connected into and between the other end of the duct and the interior of the crosshead, and a third pipe 23 connected into and between the interior of the crosshead and the bore of the other bus tube.

The concave face of the semi-circular closed end and of the U-shaped strap is opposed to the concave shoe face and, when the electrode is gripped within the clamp, is concentric to the said shoe face and to enhance the ability of the closed strap end to grip the electrode, upwardly and downwardly extending electrode-contacting flanges 25 are provided on its edges so as to increase the effective width of the said end. A rib 26 formed on and extending around the external face of the closed end and along the sides of the strap, enhances the strength of the strap.

Hooks 27 are provided on the strap and holder to serve as anchorages for the eyed ends of suspension wires 28 of an apertured heat shield 29 through which the gripped electrode passes and which protects the holder, shoe and strap from heat radiated from the furnace. The engagement of the eyed ends of the wires with the hooks enables the shield to expand and contract without restriction so that buckling of the shield is minimised.

By removing the pivot pin of the forked lever from the base of the holder, withdrawal of the branches of the lever from the slots in the sides of the strap is permitted, whereupon the said sides may be withdrawn from between the pairs of lugs on the holder cheeks and, after unbolting the shoe from the bus tubes, the said shoe may be removed from the holder. Further, the holder itself may be dismantled by removing the bolts whereby it is assembled to the flanged end of the crosshead. Hence, should any one of the clamp components develop a fault, it may be dismantled and replaced quickly and easily.

To reciprocate the strap relatively to the shoe, the upper end of the forked lever may be connected by a removable pin (not shown) to the piston rod of a hydraulic or like cylinder (also not shown) mounted upon and externally of the furnace, the said rod being loaded by a spring tending to displace it longitudinally in the direction which causes the operating lever to urge the strap towards the shoe so as to maintain the gripping eflect cf the shoe and strap on the electrode; if and when it is desired to release the electrode for any reason, fluid described and shown.

We claim: g

1. An electrode clamp comprising a U-shaped holder having a base and side cheeks, a current conducting shoe accommodated within, and supported upon the base of, the said holder, a U-shaped strap having a base and sides, of which the base spans and the sides embrace and slidably engage the said cheeks, a forked lever having arms which embrace and are pivoted upon the base of the holder and engage the sides of the strap, and means for swinging the lever about the arm pivots to slide the strap relatively to the holder towards the shoe so as to' grip an electrode, which extends through the clamp, between the ,shoe and the base of the strap.

one of said cheeks and projecting beyond the lugs towards the base of the holder, a forked lever having arms which embrace and are pivoted upon said holder base and en gage respectively with the said strap sides, and means acting on said lever for turning the said arms about their pivots and sliding the strap relatively to the holder towards the shoe so as to grip an electrode, which extends through the clamp, between the shoe and the base of the strap.

3. An electrode clamp comprising a U-shaped holder having a base and side cheeks, a current conducting shoe accommodated between the cheeks and supported upon the base of said holder, a U-shaped strap having a base and sides, the said strap base spanning and the said strap sides embracing and making respective sliding engagement with the said cheeks and each having a slot extending therethrough, a forked lever having arms which embrace and are pivoted upon the base of the holder and each of which extends through the slot in a corresponding one of said strap sides, and means acting on said lever for turning the said arms about their pivots and sliding the strap relatively to the holder in the direction which moves the strap base towards the shoe so as to grip an electrode extending through the clamp, between the said shoe and strap base.

4. An electrode clamp comprising a U-shaped holder having a base and side cheeks, a crosshead upon which the said base is detachably assembled, a pair of current conducting bus tubes, a current conducting shoe accommodated within, and supported upon the base of, said holder and having a lip which overhangs said base and is detachably assembled to said bus tubes, a U-shaped strap having a base and sides, mounted on and externally of the holder with its base spanning and its sides embracing the said cheeks, a forked lever having arms which embrace and are pivoted upon the holder base and engage respectively with said strap sides, and means acting on said lever for turning the said arms about their pivots in the direction which moves the strap sides towards the s,oee,444.

shoe so that an electrode" extending through the clamp is gripped between the shoe and the base of the strap.

5. An electrode clamp comprising a U-shaped holder having a base and side cheeks, a hollow crosshead upon which the said base is detachably assembled, a pair of bus tubes, a currentconducting shoe accommodated between the cheeks and supported upon the base of the said holder and having a duct extending therethrough pipes connecting the interiors of the crosshead and bus tubes to the opposite ends of said duct toprovide a path for a circulating fluid coolant, a U-shaped strap having a base and sides mounted on and externally of the holder with its base spanning and its sides embracing and slidably engaging the said cheeks, a forked lever having arms which embrace and are pivoted upon the holder base and respectively engage the said strap sides, and means acting on the lever for turning the said arms about their parts in the direction which moves the strap base towards the shoe so as to grip an electrode extending through the clamp between the said strap base and shoe.

6. An electrode clamp comprising a U-shaped holder having a base and side cheeks and a platform which projects from one'end of said base between the said cheeks, a current conducting shoe accommodated within the holder and supported upon the said platform the surface of the shoe adjacent the holder base being recessed and its opposite surface being concave in transverse secstrap having a curved base which spans said tion, a cheeks and of which the current surface faces said con cave shoe surface, and sides which embrace and slidably engage said cheeks, said sides reaching to the holder base and having longitudinal slots therein, and a forked lever having arms which embrace and are pivoted upon the holder base and extend respectively through said slots so that by turning the lever about the pivots of said arms in the direction which moves the strap base towards the shoe, an electrode extending between the shoe and strap base, is gripped in the clamp.

7. An electrode clamp comprising a U-shaped holder having a base and side checks, at current conducting shoe mounted upon the said base between the said cheeks, a pivot pin extending through the said base and projecting beyond the said cheeks, a U-shaped strap having a base and sides mounted upon the holder with its base spanning and its sides embracing and slidably engaging the said cheeks, and a forked lever having arms which embrace the holder base and are pivoted respectively upon the projecting ends of said pin and which engage respectively with the sides of the strap so that by turning the lever upon the pin in the direction which slides the strap sides upon the holder cheeks and moves the strap base towards the shoe, an electrode extending between the shoe and strap base, is gripped within the clamp.

8. An electrode clamp comprising a U-shaped holder having a base and side cheeks, one end of the said base being provided with a platform which is located between the cheeks and each cheek being provided with a pair of parallel lugs on its external surface, a current conducting shoe supported within the holder upon said platform, a U-shaped strap having a base and sides mounted upon the holder with its base spanning the said cheeks and its arms embracing the said cheeks and making respective sliding engagement between and projecting beyond the said pairs of lugs, each of said strap sides having a longitudinal slot in its end projecting beyond the correspond ing pair of lugs, a forked lever having arms which embrace the holder base and extend respectively through the slots in the strap sides, and a pivot pin extending through the holder base and the fork arms so that, by turning the lever' about the said pin in the direction which slides the strap sides between the lugs and moves the strap base towards the shoe grips an electrode extending between the strap base and shoe, within the clamp.

9. Anelectrode clamp comprising a U-shaped holder having a base and side cheeks, a current conducting shoe accommodated between the said cheeks and supported upon the said base, a U-shaped strap having a base and sides mounted upon the holder with its base spanning and its sides embracing and slidably engaging the said cheeks, a forked lever having arms which embrace and are pivoted upon the holder base and engage respectively with said strap sides, hooks provided upon opposite sides of the holder base and upon the strap base, and a References Cited in the file of this patent UNITED STATES PATENTS Molmark Feb 19, 1929 Carleton Ian. 25, 1955 

